/* 弹窗 (background) */
.modal {
    display: none; /* 默认隐藏 */
    position: fixed; /* 固定定位 */
    z-index: 1; /* 设置在顶层 */
    left: 0;
    top: 0;
    width: 100%; 
    height: 100%;
    overflow: auto; 
    background-color: rgb(0,0,0); 
    background-color: rgba(0,0,0,0.4); 
}
 
/* 弹窗内容 */
.modal-content {
    background-color: #fefefe;
    margin: 15% auto; 
    padding: 20px;
    border: 1px solid #888;
    width: 80%; 
}
 
/* 关闭按钮 */
.close {
    color: #aaa;
    float: right;
    font-size: 28px;
    font-weight: bold;
}
 
.close:hover,
.close:focus {
    color: black;
    text-decoration: none;
    cursor: pointer;
}
/* https://blog.csdn.net/jiehuobao/article/details/105312206 */
/* http://px.epx365.cn/runoob/runoob/w3cnote/javascript-modals.html */